Method for forming precision liquid/vapor separated bristle assembly

ABSTRACT

A bristle assembly for measuring steam quality in a well is made by slotting a metal sheet to form parallel bristles extending from a flange at one end of the sheet to the opposite end of the sheet, bending the flange to form a right angle with the bristles, and rolling the flange into a cylindrical shape with the bristles projecting radially outward.

CROSS REFERENCE TO RELATED PATENT

The present application is related to U.S. Pat. No. 4,736,627 issuedApr. 12, 1988.

BACKGROUND OF THE INVENTION

The present invention relates to the production of liquid hydrocarbonsand more particularly to the production of liquid hydrocarbons using invarious thermal methods.

In recent years, as a result of decreasing reserves and increasingprices, the use of various thermal methods to produce heavy crudedeposits has become economically attractive. In the most common thermalrecovery process steam is injected by means of a well into the heavycrude deposit to reduce the viscosity thereof and allow the crude to beproduced. Various methods have been used in thermal recovery, forexample, in one method the steam is injected and the formation isallowed to soak and the crude drains into the well from which it issubsequently produced. In another method steam is used to drive thecrude from one well toward another well. In all these cases it isdesirable to know the injection profile of the steam entering theformation through the perforations in the well casing. Also, it isdesirable to know the quality of the steam actually entering theformation so that the BTU input to the formation can be determined. Theefficiency of the recovery can be calculated and steps taken to improvethat efficiency.

The above referenced patent describes a method by which the quality ofthe steam entering a formation may be measured. The apparatus includes awire bristle arrangement which is used to separate the liquid from thevapor in the steam and permit the measurement of the quantity of liquidseparately from the vapor. This permits one to determine the actualquality of the steam at the point of injection. Also, the apparatus canbe used to determine the quality of steam at various depths in thewellbore and thus the actual profile of the steam quality can beaccurately measured.

The '627 patent relies upon a wire bristle arrangement in which thebristles bear against the inner wall of the well casing to separate thewater from the vapor and funnel the water toward the center of theapparatus. The patent discloses a bristle arrangement in whichindividual wire bristles are clamped to a mandrel arrangement to providean arrangement in which the bristles project radially outward from themandrel. The overall diameter of the bristle arrangement is larger thanthe diameter of the well casing so that as the bristle arrangement islowered into the well casing the bristles will bend upwardly and thusfunnel the liquid that is separated from the vapor toward the center ofthe instrument. The bristles are deformed into a cusped-shaped convexupward as the tool is lowered into the well. Conversely, as the tool ispulled up the casing, the bristles invert and form an umbrella-shapedregion convex downward. As vapor and liquid flow through the bristles,the drag force caused by fluid flow depends on the vapor and liquid flowrates and upon whether the bristles are pointing "up" or "down." In theformer case, total drag depends more strongly on liquid flow rate, sincethe liquid path is more drastically altered.

The '627 patent discloses the use of braided stainless wire for formingthe individual bristles. The individual bristles are attached by eitherwelding their inner ends to the mandrel or clamping them to the mandrelby suitable means. As explained in the patent, the use of welding toattach the bristles to the mandrel or central assembly of the tool isnot desirable since the heat of welding affects the mechanicalproperties of the bristles and reduces their effectiveness. Whileclamping overcomes the effects of welding, it does pose a problem indistributing the bristles in a uniform arrangement around the mandrel.The multiple rows of bristles also require a complicated clampingarrangement to properly space the individual rows of bristles andprovide a uniform bristle arrangement that will separate all of theliquid from the vapor.

Accordingly, the present invention is directed to overcoming these andother problems experienced by the prior art.

SUMMARY OF THE INVENTION

The present invention solves the above problems by providing a uniquemethod for forming the bristles. In particular, the method comprisesutilizing a flat sheet of relatively thin metal and then slotting themetal to provide the individual bristles. The slots are uniformly spacedand extend from one edge of the sheet to the adjacent side but terminateshort of the edge. This provides a narrow edge for connecting theindividual bristles together. After the sheet is slotted the unslottedportion of the sheet is bent at right angles to the slotted portion toform a flange. This flange is then rolled into a cylinder and the edgeis secured to provide an individual row of bristles. Multiple rows ofthe bristles can then be stacked and mounted on a suitable mandrel toprovide the required bristle assembly.

From the above brief description of the invention it will be appreciatedthat the individual bristles are all of a uniform size and equallyspaced from each other. Further, the bristles all extend equal distancesoutward from the mandrel. By mounting multiple rows of the bristles on amandrel one can provide a bristle assembly in which the bristles are alluniform size and uniformly positioned. Thus, the assembly will have ahigh efficiency for separating the liquid from the vapor as described inthe above referenced patent.

The bristles can be sized and arranged as called for in the '627 patentto form a network that extends across substantially the entire crosssectional area of the well casing at the location of the bristles. Usingthe bristle assembly of the present invention it is easy to position thebristles of the individual rows of bristles so that they overlap eachother and substantially cover the entire cross sectional area of thewell casing. The use of flat bristles instead of round wire ones alsoassists in separating the liquid from the vapor and reduces the forcerequired for reversing the bristles from an upward pointing direction toa downward direction as described in the '627 patent.

Various materials may be used for the bristles but preferably, a springmaterial is used to provide the action desired from the bristleassembly. In particular, non-corrosive spring-like metals, for examplestainless steel, INCONEL® (a nickel-chromium-iron alloy manufactured byCabot Corporation) and HASTELLOY® (anickel-chromium-molybdenum-tungsten-iron alloy manufactured by CabotCorporation) are preferred.

Other purposes, distinctions over the art, advantages and features ofthe invention will be apparent to one skilled in the art upon review ofthe following.

BRIEF DESCRIPTION OF THE DRAWINGS

The actual construction, operation, and the apparent advantages of thepresent invention will be better understood by referring to the drawingsin which like numerals identify like parts and in which:

FIG. 1 is a view of a portion of a sheet showing the slots which areused to form the individual bristles of the assembly.

FIG. 2 is an end view of the member shown in FIG. 1 with the flange bentupward on end.

FIG. 3 is a section along line 3--3 of FIG. 2.

FIG. 4 is a larger section of the bristle assembly showing the flangebent upward and rolled into a circular configuration.

DESCRIPTION OF THE PREFERRED EMBODIMENT

Referring to FIG. 1, there is shown a portion of the flat sheet used forforming one row or layer of bristles of the assembly. The sheet 10 isproperly sized so that when the flange is rolled into a cylindricalconfiguration the overall diameter of the bristles will be the desireddiameter. As explained above, the sheet preferably is non-corrosivemetal material that is relatively thin but has good spring action. Ithas been found that when constructing a bristle assembly for theinstrument described in patent '627 for running in a 6.366-inch casing,material having a thickness of 0.007 inches is satisfactory. For thissize assembly the bristles should extend 3.411 inches from the flangeand the sheet should be 4.0237 inches by 3.938 inches, for a 1.0-inchdiameter tool body.

A plurality of individual slots 11 are formed in the material with theslots extending from the right hand edge to a position 14 adjacent theleft hand edge 13 of the material. The slots are all of uniform widthand length and are parallel to each other. Further, the slots areequally spaced to provide a plurality of uniform bristles 12 extendingfrom the solid portion of the sheet at the left hand edge. The slotsshould have a length slightly longer than the desired length of thebristles to allow a portion of the slot to extend up into the flangewhen the material is bent. This greatly facilitates the rolling of theflange into a cylindrical arrangement. For the example given above, ithas been found satisfactory to extend the slots for a distance of 3.437inches when using 4.000-inch wide material having 0.007-inch thickness.

While the slots can be formed by various machining procedures, it ispreferable to stack a large number of pre-cut sheets and clamp themtogether. The slots can then be easily machined by electric arcdischarge machining to provide uniform slots with equal spacing. Since alarge number of sheets are machined at the same time the overall cost ofa single sheet or row of bristles is very low.

Referring to FIG. 2, there is shown the slotted sheet shown in FIG. 1with the flange with portion 13 bent upward at right angles to form theflange on the member. The flange has a width of 0.612 inches whilehaving bristles of a length of 3.411 inches measured from the surface 14of the flange. The portion 13 is preferably bent using a conventionalbrake and a rubber pad to provide a rounded corner and in addition,provide a slight curve or deflection in each individual bristle as shownat 20 in the section of FIG. 3. In particular, the portion of thebristle which occupies the first position in the radius of the bendassumes the slightly concave shape 20 as shown in FIG. 3. The slightlyconcave section greatly strengthens the bristles in the bend radius andalso increases the stiffness of the spring of the bristle. This alsoprevents breakage of the bristle at the bond point when bonding. Also,in FIG. 3, the individual slots 11 clearly extend upward into the flangemember, preferably about 0.057 inches.

Referring to FIG. 4, there is shown a larger section of the materialused for forming the bristle arrangement rolled into a cylindricalconfiguration. In particular, it is seen that as the member is rolledinto the cylindrical configuration the outer ends of the bristlesseparate into a fan-like arrangement and the edges of the cylinder maybe fastened together or it may be clamped in position. Element 21 is asupport member; a plurality of cylindrical members, each formed from asheet 10 rolled into a cylindrical configuration, are disposed on saidsupport member 21 with the bristles 12 disposed in substantiallyparallel planes and extending outward at right angles from supportmember 21. The use of several rows of bristles shown in FIG. 4 willpermit the individual bristles to overlap each other and cover thecomplete cross sectional area of the well casing.

While various configurations of bristles may be formed using variousthicknesses of material, and the bristles may have various lengths, ithas been found desirable that the bristles have an overalllength-to-width ratio of between about 40 and 70. Similarly, it has beenfound desirable for the ratio of the width of the bristle to thethickness of the material be between about 5 and 20. By maintainingthese ratios, bristles suitable for forming the liquid separating meansdescribed in patent '627 will be obtained. The width of the flange maybe approximately 5 to 20 percent of the length of the bristles. Once theflange width and the length of the bristles are obtained, one candetermine the overall width of the material while the length will bedetermined by the circumference of the cylindrical member on which theindividual rows of bristles are mounted. While HASTELLOY® has been foundto be a satisfactory material, obviously other non-corrosive materialsuch as stainless steel, aluminum, bronze or INCONEL® can also be used.

The foregoing description of the invention is merely intended to beexplanatory thereof, and various changes in the details of the describedmethod and bristle assembly may be made within the scope of the appendedclaims without departing from the spirit of the invention.

What is claimed is:
 1. A method for forming bristles to be used in abristle assembly comprising:forming a plurality of slots in a thinrectangular shaped sheet to form a plurality of narrow flat bristles,said slots extending from one edge of the sheet toward the oppositeedge, and terminating short of said opposite edge; bending the portionof the sheet adjacent said opposite edge to form a flange on said sheet,said flange including at least a portion of said slots; and bending saidflange into a cylindrical shape with the narrow strips projectingradially outward.
 2. The method of claim 1 wherein said slots areparallel and of equal width and length, and are equally spaced.
 3. Themethod of claim 1 wherein said bending is performed using a resilientpad to produce a slight bend in each narrow strip at right angles to themajor axis of the strips.
 4. The method of claim 1 wherein a pluralityof sheets of uniform size are stacked together and said slots formed bymeans of electric arc discharge machining.